Following the progress in different technological fields and in response to the consumers' demands for mobile computing, a notebook computer that allows a user to carry around has been developed for use at any place, such as at home, in the office, in a coffee shop, at the airport, on an airplane or on a bus.
Meanwhile, the quickly developed touch screen has been gradually applied to personal digital assistants (PDAs) and tablet computers. To facilitate convenient working on a tablet computer through touching the screen, the tablet computer usually includes a base, a touch screen, and a twin-rotating-axis structure for pivotally connecting the touch screen to the base. The twin-rotating-axis structure allows the touch screen to pivotally rotate relative to the base horizontally or vertically. When a user wants to operate the tablet computer, the touch screen can be turned about the twin-rotating-axis structure to face away from the base and locate thereon. That is, the base supports the touch screen thereon, so that the touch screen allows the user to touch it without causing wobbling.
However, in the case of a prior art notebook computer, the base and the display panel thereof are usually pivotally turnably coupled to each other via one single rotary shaft. This type of notebook computer is designed to open and close as a clamshell. When the clamshell notebook computer is provided with a touch display panel, the following problems will be encountered: when the display panel of the clamshell notebook computer is turned to an operation position, the center of gravity of the whole computer will move from a center of the base to one side of thereof or even to a point out of the base, bringing the whole notebook computer into an unbalanced and unstable condition. When a user touches the display panel with fingers or a touch pen, the force applied by the user's touch to the display panel on the unstable notebook computer will undesirably bring the computer to wobble, preventing the user from smoothly working on the notebook computer.